-LRB- CNN -RRB- -- All 12 of the victims killed in Monday 's shooting rampage at Washington 's Navy Yard were contractors or civilians , authorities said Monday night .

Officials identified seven of those killed . They are :

Michael Arnold , 59 ;

Sylvia Frasier , 53 ;

Kathy Gaarde , 62 ;

John Roger Johnson , 73 ;

Frank Kohler , 50 ;

Vishnu Pandit , 61 ; and

Kenneth Bernard Proctor , 46 ;

None of those killed were military personnel , authorities said .

Wounded survivors of Monday 's shooting are eligible for treatment at a U.S. military ' hospital , just as if they were soldiers wounded in war .

U.S. Navy Secretary Ray Mabus announced that Walter Reed Military Medical Center in Bethesda , Maryland , is open to them as he visited two civilian Navy workers being treated at MedStar Washington Hospital Center Monday afternoon .

Twelve victims -- and the suspected shooter -- died as a result of Monday morning 's rampage at the headquarters for the Naval Sea Systems Command , officials said . It could take another day until everyone is accounted for , the Navy secretary said Monday .

A maintenance worker who tried to warn others was among those shot , according to U.S. Navy Cmdr. Tim Jirus .

Jirus told CNN he was standing in an alley at the bottom of a fire escape supervising the evacuation of Building 197 when a worker from a nearby maintenance building approached him .

`` He walked up and told me that he heard that there was a shooter in our building , '' Jirus said . `` And we were just standing there maybe three feet away having a conversation , and then we heard two more gunshots , and he went down and that 's when I ran . ''

Jirus said he did not know the man . He was `` fairly certain he is dead , because he was shot in the head . ''

`` I do n't feel lucky that he got hit instead of me , but I feel lucky to be here , '' Jirus said .

At least one person , and possibly a second , opened fire , District of Columbia Mayor Vincent Gray said . Police said one suspected shooter was killed .

Three other shooting victims who were flown to MedStar Washington Hospital Center are expected to survive , hospital Chief Medical Officer Dr. Janis Orlowski told reporters about three hours after the attack began around 8:20 a.m. Monday .

Dr. Orlowski gave more details later in the day about her patients , including a Washington Metropolitan police officer who was in surgery Monday afternoon `` for gunshot wounds that `` involve bones and blood vessels of lower legs . ''

`` He was most concerned about being able to talk to his mother and wanted to make sure he was able to speak to her before he went into surgery , '' Orlowski said . Doctors could know after another day about the police officer 's chances of walking again , she said .

Witness : ` He aimed his gun at us ' and fired

The two other victims at MedStar Washington Hospital Center were women , including one shot in the shoulder and the other with a head wound , Orlowski said . A helicopter plucked one of the wounded women from a roof and carried her to the hospital , she said .

`` Their chances of survival are very good , '' she said . The patients were all in stable condition , she said .

The woman with the shoulder wound was `` in very , very good spirits , '' Orlowski said . `` She 's actually ordering the doctors and nurses around , and we told her we are in charge here . ''

The other woman suffered a `` significant wound '' to her hand and head , but the bullet did n't actually penetrate her skull , she said .

Her father rushed to the Navy Yard when he heard about the shooting , Orlowski said . He found her as paramedics were treating her on the scene , she said .

The three patients were each alert when they arrived at the hospital and they sometimes talked about the shooting , Orlowski said . The most common question was about the fate of their co-workers .

`` They 're very worried about their colleagues , '' she said . `` It 's the only question that I 've heard about the incident . We 've not shared that with them . ''

Mabus went to the hospital to check on the two women , who are Navy employees . `` We got to meet one of the victims , a young woman and her family , '' Maybus said . `` She is , under the circumstances , doing very well . I also got to talk to the husband of the second victim , who is in surgery right now . But none of the injuries are expected to be life-threatening . ''

Relatives of people who worked in Building 197 gathered near the Navy yard , hoping for information about their loved ones .

Jacqueline Alston said she has not heard from her husband , Ernest , who is a custodial worker there .

`` Right now , I 'm asking God to let me hear that voice , to let me see that man again , '' Alston said . `` All I know is , I 'm supposed to be patient , which I am trying to hold on , being patient and understanding , and ask God what created this problem ? What started this ? ''

Mabus said Monday that it could take 24 to 35 hours for Navy officials to account for everyone . He gave two telephone numbers people can call to check on family members who may have been at the Navy Yard . The numbers are : 202-433-6151 and 202-433-9713

`` When you call we will not be able to give you a status report , '' Mabus said . `` We 'll have to check and call back . ''

Latest developments

CNN 's Jonathan Auerbach contributed to this report .

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NEW : None of those killed were military personnel , authorities say

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A wounded cop asked to call mom before surgery , doctor says

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A Navy commander says he saw maintenance worker shot in head